AIDS Vaccine Prevents Infection in Some Groups

The phase III trials of Aidsvax (rpg120) to prevent HIV infection have revealed no significant reduction of infection in white and Hispanic volunteers given the vaccine, but they have shown a 78% reduction of infection among black volunteers and a 67% reduction among ethnic minorities other than Hispanic. A more-detailed analysis will be available in late March or early April.

The three-year, multinational, randomized, double-blind, placebo-controlled study involved 5,009 volunteers, all of whom were meant to be HIV-negative when they joined the trial. The results presented are based on volunteers who received at least the primary course of three injections of either the vaccine or a placebo. The researchers note that black and Asian volunteers given the vaccine appeared to produce higher levels of antibodies against HIV, while white and Hispanic volunteers appeared to develop consistently lower levels of protective antibodies following vaccination.

Aidsvax was developed by VaxGen, Inc. (Brisbane, CA, USA). The vaccine is composed of a recombinant form of the gp120 protein on the surface of HIV and is produced in mammalian cell culture. It includes two HIV subtype B antigens: MN and GNE8. Since the vaccine contains no genetic material from the virus, it cannot cause HIV infection.

"This is the first time we have specific numbers to suggest that a vaccine has prevented HIV infection in humans,” said Philip Berman, Ph.D., senior vice president of research and development at VaxGen and the inventor of the vaccine. "We're not sure yet why certain groups have a better immune response, but these preliminary results indicate that a surface-protein vaccine that stimulates neutralizing antibodies correlates with prevention of infection.”




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